Abstract

Breakdown of trade barriers among countries exploded the volume of international trade. Consequently, amount of bulk cargo carried in containers and transported over seas exploded due to flexibility, reliability and easy handling. Containerization started in midfifties and spread all around the world. Number and capacities of containerships as well as container terminals have increased considerably. Only in the 90’s usage of containers has increased 2.5 times. So efficiency in container terminals has become a major problem. Today container terminals serve ships that can carry 5000-6000 containers. Number of ships to be served and containers to be handled increase day by day. So efficiency during operations has become the key point, thus container terminals become perfect places for Operations Research applications. In this work we deal with a low level operational problem in container terminals. Basically efficient retrieval of containers from their stacks is considered. We try to minimize number of container relocations and total distance traveled by the crane. Problem is solved optimally using branch and bound based procedure and alternative heuristics that give near optimal solutions are proposed. In addition, a new concept to further optimize the retrieval operation is introduced, formulated and tested.